As Adverbial Clauses

Time: when / while / after / before / as soon as / by the time / since / until / as / as long as etc.

Reason: because / since / as / seeing that / inasmuch as / now that / on the grounds that

Purpose: so that / in order that / lest / in case / for the purpose that / for fear that

Contrast: although / though / even though / whereas / notwithstanding / much as

Comparison: as if / as though

Condition: if / provided(ing) (that) / so long as / unless / only if / even if / on condition that

When my father came, I had already finished my homework.Seeing that it was raining we decided not to go out.In order that I can improve my English I have decided to go to England.Although she is so beautiful I won’t marry her.
He speaks as if he was an expert.If you finish your assignment early you can go out with your friends.